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Instructions for VR-Series
Replacement Breakers for
Westinghouse Type B20B/B22B
I.B. 94A1994R01
Page 29
Effective: April 2005
IB01301018E
Figure 6-4 The Arrow Shows The “T” Contact Wipe Indicator
- Example with Blue Spring (if the “T” or any portion
of its visible as shown with the breaker closed, the
wipe is satisfactory, See Next Figure for Graphic of All
Possibilities).
6.8 PRIMARY CIRCUIT RESISTANCE CHECK
Since the main contacts are inside the vacuum chamber they
remain clean and require no maintenance at any time. Unlike most
typical circuit breaker designs, VR-Series breakers do not have
sliding contacts at the moving stem either. Instead they use a highly
reliable and unique flexible clamp design that eliminated the need for
lubrication and inspection for wear.
If desired, the DC resistance of the primary circuit may be measured
as follows: close the breaker, pass at least 100 amps DC current
through the breaker. With the low resistance instrument, measure
resistance across the studs on the breaker side of the disconnects
for each pole. The resistance should not exceed the test levels by
more than 15%. Factory test levels are recorded on the Circuit
Breaker Test Form.
6.9 MECHANISM CHECK
Make a careful visual inspection of the mechanism for any loose
parts such as bolts, nuts, pins, rings, etc. Check for excessive wear
or damage to the breaker components. Operate the breaker several
times manually and electrically. Check the closing and opening
times to verify that they are in accordance with the limits in Table
5.1.
6.9.1 CLOSURE
TM
TEST
Introduction: The CloSure
TM
Test is a simple yet extremely
effective means to determine and monitor the ability of the mecha-
nism to close the breaker contacts fully. It provides a quantitative
measure of the extra energy available in terms of over travel in
inches to close the breaker contacts to their full extent. It may be
used periodically to monitor the health of the mechanism.
At times, circuit breakers are called upon to operate MOC switches
(Mechanism Operated Control switches) that place extra load upon
White Contact Springs
Blue or Red Contact
Springs
Any part of “T” Shape Indicator
Visible “Wipe” Satisfactory
“T” Shape Indicator Not Visible
“Wipe” Unsatisfactory
Any part of Red or Gray Indicator Visible
“Wipe” Satisfactory
Red or Gray Indicator Not Visible
“Wipe” Unsatisfactory
Figure 6-5 Wipe Indication Procedure (performed Only with
Breaker Closed)
